A coordinated series of radar air navigation and traffic- control aids utilizing transmissions at wavelengths of 10 and 60 centimeters to provide in an aircraft the distance and bearing from a given point, along with a display of other aircraft in the vicinity and commands from the ground; the system also provides on the ground a display of all aircraft in the vicinity, with their altitudes, identities, and means for transmitting certain commands.Derived from navigation and ranging.